Examples of conventional sensor devices include a physical quantity sensor device described in JP-2004-294069-A (Patent Document 1), etc.
The related art described in Patent Document 1 is configured in such a manner that disconnection of a power supply line or its contact failure is detected by a reduction in power supply voltage, and a sensor output is fixed to the potential of the power supply line by turning off an output transistor when the power supply voltage decreases. This makes it possible to make a judgment as to failures such as the disconnection of the power supply line and its contact failure.